A machine (e.g., a server machine) may form all or part of a network-based system that provides one or more network-based services to one or more users. To offer personalized or otherwise customized features of the network-based service, the machine may maintain a profile of some or all of the users of the service. In some cases, the machine creates and stores a data structure (e.g., data record within a database) that describes a user, in whole or in part. Such a data structure may be referred to as a “user profile” of the user. For example, the user profile may describe the user by specifying (e.g., by inclusion or by reference) one or more characteristics of the user. Examples of such characteristics include the user's name (e.g., full name or username), address e.g., home address or email address), age (e.g., birth date), gender (e.g., sex), previous item purchased, previous item viewed, employer, job title, number of years at job, marital status (e.g., single or married), availability for online dating, favorite color, favorite movie, favorite sport, preference for smoking, preference for drinking (e.g., alcoholic beverages), or any suitable combination thereof. In some situations, any user profile may be presented (e.g., displayed), in whole or in part, by the machine (e.g., in response to a request by the user to view or update his profile).